The Genus Acer (Maples) in Formosa and the Liukiu [Ryukyu] Islands H UI-LIN Ll1 THE SPECIES of the genus Aeer in Formosa C. Leaves glaucous beneath. and the Liukiu Islands are included in the D. Leaves obtuse or cuneate at base, revisional study of the family Aceraceae made not 3-nerved . 1. A . a/bopurpuraseens by Fang (1939). The Formosan species are DD. Leaves rounded to cordate and also treated by Kanehira in his work on the distinctly 3-nerved at base . Formosan trees (1936). The opinions ex­ . .. ... .. •2. A . itoanum pressed by these two authors are widely diver­ Cc. Leaves white-pubescent beneath . gent. Fang accepts practically all the species . .. .... ... .. 3. A. hypo/eueum originally described from Formosa, whereas BB. Leaves 3-lobed . Kanehira reduces a large number to synony­ .. .4. A. buergerianzon var. formosanum my . Neither of the two treatments is exhaus­ AA. Leaves serrate. tive, as a few names pertaining to Form osan B. Leaves undivided to shallowly 3 ~ .or plants are omitted from each . rarely 5-lobed. For purposes of the present study, the C. Leaves mostly undivided, sometimes works of these two authors, as well as other shallowly 3- or rarely 5-lobed; inflo­ pertinent literature, have been critically re­ rescence racemose. viewed . Specimens deposited in the U. S. D . Fruit 2-2.2 em. long . National Herbarium, Smithsonian Institution, . ... .. ...5. A. kawakamii and the herbarium of the National Taiwan DD. Fruit 2.5-3 em. long . University, Formosa, have been studied and . 5a. A . kawakamii vat. taiton­ arecited, with the abbreviations US and NTU, montanum respectively. In the latter case, only selected Cc. Leaves distinctly 3-5-lobed; inflo- specimens are listed. As a result of this study, rescence cymose . eight species are recognized for Formosa and . .6. A . tutcberi var. shimadai one for the Liukiu Islands. The Liukiu entity BB. Leaves distinctly 5- or 7-lobed. was formerly considered a variety ofa Chinese C. Leaves all 5-lobed. species, but it is here raised to specific rank. D. Leaves shallowly 5-lobed; fruit 1.8- Two new varieties are proposed herein, and 2.3 em. long 7. A . rubescens several new synonyms are noted. DD . Leaves deeply 5-lobed; fruit 2.5 em. long 8. A . serrulatum KEY TO THE SPECIES IN FORMOSA AND Cc. Leaves all 7-lobed . LIUKIU ISLANDS . ... .9. A . pa/matum var. pubeseens A. Leaves entire. B. Leaves undivided, rarely indistinctly 3­ 1. Acer albopurpurascens Hay. (1911 : 64). , lobed. Am litseaefolitlm Hay. (1913: 66, pl. 14, b). 1 Research Associate, Morris Arboretum, ' University of Penns ylvania, Philadelphia, Pennsylvania. Manu­ Acer ob/ongum sensu Matsum. & Hay. script received January 28, 1952. (1906: 96); Koidz. (1911b: 55), p. p. ; [288 ] Acer in Formosa- Lr 289 Kanehira (1936: 506, fig. 361) [non probably only one species is present on the WalL]. island; the identity of A . hypoleucum is some­ A cer lanceolatum sensu Rehder (1905: 180) what uncertain. p. p.[non Molliard]. A plant from the Liukiu Islands, consid­ ered as a variety of A . oblongum, has distinct An evergreen tree to 15 cm. high; branch­ morphological characters and an outlying lets pubescent at first, soon glabrous. Leaves range. It should be treated as a separate persistent, coriaceous, oblong-lanceolate, 6­ species. 13 cm. long, 2.5-5 cm. bro ad, caudate to acuminate at apex , obtuse to cuneate at base , 2. Acer itoanum ( Hay. ) comb. nov. pale green and glabrous above, white-purplish­ glaucous beneath, densely pubescent when Acer oblongum Wall. var. ·itoanum Hay. young, weakly 3-nerved at base, the basal (1911: 67); Metcalf (1932: 196) ; Fang nerves short, slightly raised or indistinct, the (1939: 138). lateral nerves 7-10 per side, slightly raised , Acer oblongum var. microcarpum sensu Ito divergent at right angles; petioles 1.5-3 cm. ex Ito & Matsum. (1898: 387) [non lon g, glaucous. Infructescence cymose; nut­ Hieronymus]. lets glabrous, about 3 mm. across; wings Acer oblongum sensu Koidz. (1911 b: 55, with nutlets about 2 mm. long, spreading at pl. 29) p. p. obtuse angles. Tree to 13 m.; branchlets glabrous, the Endemic to Formosa; in forests from me­ young ones reddish, the older grayish. Leaves dium to lowaltitudes throughout the island. thin-coriaceous, glabrous, ovate to broadly Formosa: South Cape, A. Henry 1257 (US); ovate, 4.5- 6.5 cm. long, 2-4.5 em. broad , Musha, Nanto Prov. , E. H. If/ilson 10082 abruptly acuminate at apex, rounded to cor­ (US); Kizan-gun, Takao-s yu, Y. Yamamoto date at base, entire at margins, usu ally un­ & K. Mori 808 (N TU) . divided, rarely indistinctly and obtusely The concept ofA. oblongum Wall. in eastern 3-lobed, green above, glaucous beneath, Asia has been considerably modified in recent dist inctl y 3-nerved at base, the veins distinct years. The species is now considered as oc­ on both surfaces, the basal nerves lon g and curring only in northeastern India and western strongly ascending, the lateral nerves 3- 5 per Chin a, and other plants of ·this Immediate side, the veinlets densely reticulate, elevated relationship from eastern and southern China and distinct on both surfaces; petioles slender, are considered to represent distinct species to 2.5 em. lon g, glabrous. Flowers unknown. by recent authors, perhaps too many such Infructescence terminal, corymbose, pubes­ species being recognized. Hayata earlier es­ cent; peduncles about 1 cm. long; pedicels tablished three species of this group in For­ to 1 cm. lon g, slender, pubescent. Fruit mosa, namely A. albopurpurascens, A . litseae­ brownish yellow; nutlets convex, 5-6 mm. folium, and A . hypoleucum , but later workers long, 3-4 mm. broad; wings oblong, with on the Formosan flora, including K anehira nutlets about 1.5- 2 cm. long, 5 mm. bro ad, (1936) and Sasaki (1930: 325), consider them spreading at abo ut 45-90°. as a single species , to which they refer as Endemic to the Liukiu Islands. A. oblongum Wall. Metcalf (1932: 198) and Liukiu Islands: Okinawa, W. D. Field & Fang (1939: 145-163) maintain all three as o. G. Loew 4 (US); Shuri, E. H. Wilson 8172 distinct. The Formosan plant, under the cur­ (US), C. Wright 40 (US). rent concept, should be specificall y distin­ This species differs from A. oblongum Wall. guished from A . oblongum especially because in the small, short, ovate leaves, which are of the weak or indistinct basal nerves. But abruptly acuminate at apex and distinctly 290 PACIFIC SCIENCE, VoL VI, October, 1952 rounded to cordate at base, as well as in the Acer trifidum Hook. & Am. vat. formosa­ smaller fruits with pubescent. pedicels. The ntanHay. ex Leveille (1906: 593); Koidz. win gs of the fruit are oblong rather than (1911b: 30, pl. 17,8-9); Kanehira (1936: ovate in shape. Among the specimens cited, 409, fig. 364). Field & Loew 4 has the leaves mostly broader Tree to 10 m . high ; branchlets glabrescenr. and more distinctly cordate, with a few having ·Leaves deciduous, membranaceous, ovate to a ten dency toward being indistinctly 3-lobed. elliptic, 8-10 em . long, 4-6 em. broad, round­ The illustration given by Koidzumi, showing ed or slightly cordate at base, entire or leaves with round to cordate bases, evidently shallowly 3-lobed near ape x, 3-nerved at base, refers to the Liukiu plant. the reticulations conspicuous; petioles 2.5-5 3. Acer hypo leucum Hay. (1913: 66, pl. 14, em. long. Inflorescence corymbose. Fruits c) . yellowish brown; nutlets strongly convex, about 6 mm. across; wings falcate, with nut­ Small tree; branchlets slender, tomentose lets 2.5-3 em. long, 8-10 mm. broad, spread­ at first, soon glaucous. Leaves persistent, ing horizontally. chartaceous to coriaceous, oblong or elliptic­ Formosa: Huki-kaku, T. Kawakami, M ay oblong, about 8 em . long, 3.5- 4 em . broad, 1915 (N TU) . obtuse or acutish at apex, rounded or obtuse The species occurs in southeastern China, at base, entire or slightly undulate at margins, the variety is endemic to the coast ofnorthern green above, whitish-glaucescent and densely Formosa, in forests. Fang maintains the varie­ tornentose beneath, slightly 3 ~ n er v ed at base, eryon the basis of the type specimen, which the nerves raised and more or less distinct, he examined. the lateral nerves 5 or 6 per side; petioles 2-3 em . long, slender, tomentose. Infruc­ 5. Acer kawakamii Koidz. (191la: [102] tescence cymose, terminal; nutlets convex, [March]; 1911b: 15, pI. 5 [Aug.]); Kane­ about 5 mm. across; wings with nutlets about hira (1936: 402, fig. 360). 17 mm. long and 6 mm. broad, spreading at Acer caudatifolium Hay. (1911: 65 [June]). nearly right angles; pedicels 1.5 em . long, Acer morrisonense Hay.(1911: 66, ex K oid z. slender, pubescent. 1911a: 16, pl. 7). Endemic to Formosa; no specimen seen . A cer ovatifolimn Koidz. (1911a: [102]); A cer bypoleucton is described as being pubes­ (l911 b: 16, pl. 6). cent on the lower surface of the leaves. It is Acer caudatum sensu Matsum. & H ay. thus maintained as distinct from A. albopur­ (1906: 96) [non Wall.] . purascens by Metcalf and Fang; the latter has seen the type. However, Kanehira relegates A tree to 20 m. high; branchlets slender, it, together with A . albopurpurascens, to the glabrous. Leaves deciduous, chartaceous, synonymy of A . oblongum (sensu Kanehira ovate to ovate-oblong, 6-10 em. long, 3-5 em. non Wall. ). In A. albopurpttrascens, the young broad, caudate-acuminate at apex, rounded leaves are densely pubescent, as shown in or slightly cordate at base, serrate and some­ Wilson 10082. The presence or absence of times shallowly 3- or rarely 5-lobed at mar- these hairs may be due to variation in age .